Wire printing method

ABSTRACT

A printing method for use with a wire printer designed for improved printing of both higher and lower case alphabetical characters wherein additional printing points and positions are added to write better-formed characters, and especially to print improved characters having diagonally extending and curved segments.

United States Patent ACTUATOR 2a cHmc TER ENERGIZER LOGIC IBM TechnicalDisclosure Bulletin, Vol. 7 No. 9, Feb. 1965, article by K. Heydkampentitled Selecting Type Size In Matrix Printers pages 815 and 816Primary Examiner-Edgar S. Burr Attorneys-Hanifin and Jancin and GeraldL. Moore I ABSTRACTt A printing method for use with a wire printerdesigned for improved printing of both higher and lower casealphabetical characters wherein additional printing points and positionsare added to write better-formed characters, and especially to printimproved characters having diagonally extending and curved segments.

- INPUT DATA SIGNAL Patented Dec I4, 171 EMZKQQ 2 Sheets-Sheet 1L I n lI ll I I I I I I I I 14 l ,1

INPUT DATA SIGNAL EDWARD D. FINNEGAN BY 3 Wm ATTORNEY CROSS-REFERENCESTO RELATED APPLICATIONS This invenhon is designed for use with such wireprinting heads as that described in the copending U.S. Pat. applicationSer. No. 764,474 entitled Wire Printing Head, filed on Oct. 2, 1968 withE. A. Brown and A. S. Chou asinventors and assigned to the assignee ofthe present invention.

BACKGROUND OF THE INVENTION In wire printing wherein the characters areformed by stamping a series of dots on a record member, which is usuallypaper, the square alphabetical symbols and numbers are formed in aclearly legible manner by the use of a normal dot matrix. Even wherediagonal lines must be formed, so long as these lines extend generallyat 45 from the vertical, not too much diificulty is encountered informing good appearing characters. However, a close investigation ofmany of the upper case alphabetical symbols and numbers shows thatdiagonal lines are needed extending at other than 45 for the properformation of legible images. When printing the lower case alphabet, itis found that the character quality sufiers even more when limited tothe 45' diagonal lines.

In the past, such wire printing has been effected by a series of dots,usually in a X7 matrix, positioned adjacently but not overlapping in thevertical plane, thereby limiting the angle at which the diagonal linescan be formed. The primary reason for forming such characters was thatthe wire actuators could only be energized for printing the respectivedots at predetermined time intervals. Thus, to improve the quality ofthe characters formed, a compromise had to be achieved between thequality of the characterand the speed of the printing operations sincewire printers usually are employed where speed and cost are factorsconsidered at least as important as the quality of the type. Thus, anycompromises have generally involved lessening the legibility of theprinting and increasing the speed of the printer.

The primary purpose of this invention is to effect good qualitywire-matrix printing with little reduction in the printing speed and atlittle or no additional cost of the wire printing device.

SUMMARY OF THE INVENTION A method for forming characters with a wireprinting device wherein the wires are actuated at predetermined timeintervals but in a staggered fashion to form dots overlapping in thevertical plane thereby rendering more legible characters. Additionallythe printing method of the subject invention teaches the employment of awire printing device having strategically positioned printing wires forprinting better quality upper and lower case characters.

Other objects and advantages of the invention will become apparent fromthe following detailed description taken in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I illustrates one type of wireprinting device in which the subject invention can be employed.

FIG. 2 illustrates on an enlarged scale one example of charactersprinted by use of wire printing devices employing previously knownmethods.

FIG. 3 illustrates the better quality upper case characters printed byuse of one embodiment of the subject invention.

FIG. d shows one example of numbers printed with wire printers presentlyused.

FIG. 5 shows the better quality numbers that can be printed by using anembodiment of the subject invention.

FIG. 6 illustrates the printing end of a print head employing oneembodiment of the subject invention.

FIG. 7 illustrates the printing end of a print head employing anotherembodiment of the subject invention, and

FIG. 8 illustrates selected lower case alphabetical symbols which can beprinted by using the embodiments of the invention shown in FIG. "7.

DESCRIPTION OF PREFERRED EMBODIMENTS The subject invention preferably isembodied in a printer head such as that shovim in FIG. I and describedin detail hereinafter. In such a wire printer head It), individual wiresit are actuated to press an inking ribbon 12 into contact with a recordmember such as the paper 113 resting against a platen I4 for printingcharacters comprised of a plurality of dots or impressions. In theembodiment shown, electromagnetic actuators 15 are energized to actuateeach wire as needed to form the desired character as the head istranslated across the paper. For translating the head, a rotatablethreaded shaft 16 is passed through a threaded opening 17 in the frame118 of the head to drive the assembly sidewise. An additional shaft 19passing through a close fitting opening 20 in the frame holds the headsteady as it is translated.

While not shown in detail, the individual actuators 15 generallycomprise an electromagnet having an armature fastened to the wire Illfor movement thereof lengthwise through a wire guide 21. The guide isfastened to the frame by the screws 21a and extends from a position nearthe actuators to a location closely adjacent the platen M. The inlringribbon is fed around the rollers 22 and across a guide 2d between thewire ends and the paper.

The individual actuators lid are energized by the transmission of anelectric current signal to the associated conductor 25 extending from anactuator energizer 2b. In response to the input data signal calling foraspecific character to be printed, the character code logic circuit 27determines which of the wires should be actuated at each position andfeeds the signal through the conductor 28 to the actuator energizer. Inthe past, the characters were formed by actuating selected ones of theseveral wires (usually seven) at each of several distinct and spacedpositions (usually five in number) for printing the selected symbol.

Thus, in the presently used printers, the individual wires are actuatedin synchronization with the translation of the head to form characterssuch as those indicated in FIG. 2 of the drawings. In this figure, theupper case letters are shown and it can be noted that little difficultyis encountered in printing a very legible character if the letters aresquare and do not call for curved or diagonally extending lines. Forinstance, the alphabetical characters "T" and E" are shown in FIG. 2printed in a normal manner of firing a seven-wire printing head at livelaterally spaced positions to form a 5X7 matrix. It can be noted thatthe quality of the Ietters T and E is very good. In the same figure, areshown the higher case letters involving various diagonal and curvedlines such as the D" 0." It can also be noted that such characters asthese come out irregular in shape in that the diagonals needed to formthe characters do not fit the diagonal lines: necessary to form theletters properly. Specifically, the characters V, A, Y, W and X aredifificult to form and the printing thereof with a 5X7 matrix can resultonly in a distorted character. While the characters can be read, theyare not precise and distinct in form.

In FIG. 3 are shown various characters corresponding to those of FIG. 2and which are printed by the subject invention. The improvement in theaesthetic qualities of the higher case characters if readily seen incomparing the characters of FIGS. 2 and 3. The characters in FIG. 3 areprinted in accordance with the present invention by triggering or firingthe wires at the normal five spaces as was accomplished in printing thecharacters in FIG. 2, and additionally by firing at half spacespositioned in between and in overlapping relationship to the fivespaces, thereby making a total of nine positions overlapping orstaggered in the vertical plane at which each wire can be triggered. Theonly qualification in the printing operation is that each firing of awire must be spaced by a full print position, i.e., a complete spacemust exist between each position at which the wire is actuated. Toelaborate on this requirement, if a wire is printed at half position,then the next possible location at which it can be printed or fired isat the next half position following that position. This requirement isnecessary because a reset time must be allowed the printing head beforethe wire can again be actuated to the print positron.

By accomplishing the printing of the higher case alphabetical charactersin this manner, an overlap between adjacent vertical dots in thevertical plane normal to the direction of head movement is achieved toform diagonal lines positioned at 30 from the vertical and to fit theneeds for many of the higher case characters. As can be seen, theimprovements in such characters as the O, V, A, Y and X are readilyapparent because the diagonal lines now available with the 9X7 overlapmatrix more distinctly fit that needed to print those characters. Thus,the continuous straight line in the diagonal segments of the charactersnecessary for printing X, Y and V's can be formed. For instance, withthe X, the dots of the diagonal are printed every other one at thehalf-line position to form the diagonal segment as a continuous straightline. To

illustrate, the dots 30 and 31 in FIG. 3 are printed at the standardfiring positions while the dots 32 and 34 are positioned at thehalf-fire positions. Note that the adjacent dots 31 through 34 overlapin the vertical plane to enable the formation of the straighter linesextending diagonally across the plot of the normal 5X7 matrix. Thus,dots which overlap" are dots printed at adjacent half-fire positions bydifferent wires.

The heretofore described invention is also advantageous in printingnumbers as is shown in FIGS. 4 and 5. In FIG. 4 are shown the numbers aspreviously printed and it can be noted readily that irregularly curvedsegments occur in such numbers as the 3, 6, 8 and 9 while irregulardiagonal lines exist in the printed numbers 4 and 7. In FIG. 5, thesubject invention is used in which the print wires are fired at the halfpositions. The improvement in the quality of the numbers is obvious. Forinstance, the number 2 is well-rounded with the dots 35, 36 and 37overlapping in the vertical plane. The improved number 7 embodies astraight diagonal line formed by firing every other wire at thehalf-fire position. Improvements in the other numbers also are noted,i.e., the is now the more pleasing oblong configuration instead of beingsquare. The 6 also is improved by utilizing the diagonal line withoverlapping dots achievable with the present invention. Thus, theadvantages of the present invention are readily obvious in printing boththe higher case alphabetical characters and the numeric characters.

Referring now to FIG. 9, the relationship between the various printpositions will be described. Dots 51-55 are printed by a single wirewhich is caused to scan at an essentially constant velocity across thepaper. Each dot 51-55 is printed at what is defined as a full position.Dots 71-74 are similarly each printed by a given wire but at halfpositions. In this figure, there are five spaced vertical rows, eachheaded by a dot 51-55, and 7 horizontal rows forming a X7 matrix, withfour half position vertical rows including dots 71-74.

The relationship between the various dots with respect to the distanceof travel of the print head while printing is explained as follows.Referring to dots 81-83, the distance d is defined as the distancetraveled by the print head 10 in the minimum time required to actuate agiven wire 11 twice and is related to the mechanical and magneticcharacteristics of the print head requiring that a reset time be allowedbefore a given wire can be actuated to the print position again, forexample, to form dot 82 after 81. The actual print timing for the headis established such that the distance d between dots 54 and 55 is equalto or greater than the distance d and such that the distance 55d betweendots 54 and 65, 74 is greater than d. With this requirement, it isapparent that it would be impossible to fire a print wire to form, forexample, dots 84 and 85 where 85 is on a half position adjacent to thefull position of dot 84.

The above discussion has been with respect to the distance d, d oftravel of the headand was described in terms of a 5X7 matrix with halfpositions. Now, consider the spacing L, L of possible print positions ona paper. As'shown in FIG. 9, there are nine vertical rows and sevenhorizontal rows, forming what may be considered a 9X7 matrix. Eachintersection of vertical and horizontal rows represents a potentialprint position. Once again, L is defined as the space on the papertraveled by the print head in the minimum time required to fire, reset,and fire again. The spacing L between adjacent vertical rows of the 9X7matrix is defined as being less than L, where 2L is equal to or greaterthan L. With this requirement, it is apparent that it would beimpossible to form print dots 84 and on ad- 5 jacent vertical rows ofthe 9X7 matrix. Herein, the L and L dimensions are associated with the9X7 matrix, and the d' and d dimensions are associated with the 5X7matrix with four half positions.

In accordance with a second embodiment of the invention, upper and lowercase letters can be printed with the same writing head by the use ofadditional wires positioned below the standard 7 wire alignment and usedonly to print the lower case characters. For instance, in the embodimentshown in FIG. 6, one preferred embodiment incorporates the aligned sevenprint wires for printing upper case letters and two additional printwires used only for printing the lower case letters. In this embodiment,the print wires positioned below the dotted line 38 and numbered 39 and40 are used only to print lower case alphabetical character and are notused to print higher case alphabetical characters and numericcharacters. The advantages of this embodiment are shown in FIG. 8whereinmany lower case letters demand an extension below the normal baseline of. the higher case characters. For instance, the characters g, j,p, q and y extend below the line while the other lower case charactersonly extend above the print line. Thus, a method is provided forprinting lower case characters by utilizing the top seven wires forprinting most of the lower case alphabet and printing with the wires 39and 40 positioned below the line only when the specific characters areto be printed which demand an extension below the print line. In thismanner, the same print head can be utilized for printing both upper andlower case characters. In addition, the comma and semicolon are morelegible as shown in FIG. 8. It is also known that foreign alphabets andirregular shapes are formed more easily with this embodiment of theinvention.

In accordance with another embodiment of the invention, there is shownin FIG. 7 a printing head which embodies the print wires positioned in avertical plane and in addition, incorporates an additional print wire 41positioned adjacent the third and fourth wires 42 and 43 and at thehalf-fire position partially between those wires. Of course, thehalf-fire position of the additional wire could also precede those wireswith the same effect being rendered by firing this wire at the nextfollowing position while printing the character. It has been discoveredthat in printing such lower case alphabetical characters as the b, d g,h, k, m, p, q, r, x and z, the additional wire position is needed tofonn a more perfect character. For instance, as shown in FIG. 8, theselower case alphabetical characters are formed in a much more precisemanner in utilizing this additional wire. The dots numbered 410 allcorrespond to printing by the wire 41. It will be noted this dotlocation particularly enhances the printing of several of thecharacters.

There also is shown in FIG. 7 an additional wire 44 positioned adjacentthe sixth and seventh wires 45 and 46 at the half-fire position. Thiswire is especially useful in printing many of the same characters asshown in FIG. 8 because they more logically form these characters in themanner in which they are normally written. For instance, in printing thelower case print a, b, c, d, e, g, h, k, m, n, a, p, q, r and s, the dot4lafor'ms an integral part of the diagonal segment and enables theprinting of a well-formed character. The wire 44 is used in forming thedot numbered 44afor printing more accurately the characters a, b, e, g,0, p, q, u, w and y. Thus, the half-firing of the print wires print beeliminated, i.e., operate with a 5X9 print matrix instead of a 9X9 as issupplied in the half-firing head, and still a more readable character beprinted. While the invention has been particularly shown and describedwith reference to preferred embodiments thereof, it will be understoodby those skilled in the art that various changes in the form and detailsmay be made therein without departing from the spirit and scope of theinvention.

What is claimed is: l. The method of printing upper and lower casecharacters on a record member with a wire printing machine having aprinting head comprised of a plurality of print wires, said methodcomprising the steps of:

effecting relative movement at an essentially constant velocity betweenthe head and record member;

selectively actuating said wires at predetermined intervals to formspaced imprints in a preset number of spaced rows, each row being spacedby a full position of distance d where d is equal to or greater than thedistance d traveled by said head in the minimum time required to actuatea given wire twice and where [5a d', 1 Aral d', and;

selectively actuating said wires for imprinting said record member athalf positions between and overlapping adjacent spaced rows in the planenormal to the direction of relative movement between the member and headwith each actuation of a given wire forming imprints spaced by at leasta distance d from the previous imprint of said given wire for formingthe angular extending portions of the characters desired to the printed.

2. The method of printing as defined in claim 11 wherein said step ofeffecting relative movement further comprises the step of scanningparallel noncolinear print lines on said record member with a pluralityof print wires arranged in a straight row.

3. A printing head for printing on a record member comprising aplurality of printing wires having a first end positioned adjacent saidmember and the second end positioned remote to said member,

an actuator for each wire operable upon energization to propel said wirefirst end into contact with said member for leaving an imprint thereon,

means for effecting relative movement at an essentially constantvelocity between the head and record member,

a wire guide positioned between the actuators and record memberfunctioning to align the wires in a single row extending normal to thedirection of relative movement between the head and member,

means for energin'ng said actuators at preselected spaced positionsalong said member for imprinting said member to form a matrix of spaceddots forming characters desired to be printed, said matrix having rowsseparated by full positions of distance d, where d is equal to orgreater than the distance d' traveled by said head in the minimum timerequired to actuate a given wire twice, and where /td i',

means for energizing selected ones of said actuators at intermediatepositions bett veen said rows of said matrix and in vertical overlappingrelationship with said rows for forming angular extending segments ofcharacters, each said actuator being energized to form dots in saidmember spaced by at least a distance d.

4. A printing head as defined in claim 3 wherein seven printing wiresare positioned in a single row for printing a line of impressionsextending normal to the direction of movement between the head andrecord member.

5. The method of printing characters on a record member with a wireprinting apparatus having .a print head including a plurality of printwires, comprising the steps of:

effecting relative movement at an essentially constant velocity betweenthe head and record member with said wires scanning parallel noncolinearprint lines across a lurality of character print positions on saidmember; se ectively actuating said wires to form a matrix of dotsforming the characters desired to be printed, the rows of said matrixbeing separated by a distance L where 2L is equal to or greater than thedistance L traveled by said head in the minimum time required to actuatea given wire twice and where L L' and selectively actuating each givenwire to form dots-and, spaced by at least the distance L' from the dotformed by the previous actuation of said given wire.

t v! =1 *3 l IOIOH 0050

1. The method of printing upper and lower case characters on a recordmember with a wire printing machine having a printing head comprised ofa plurality of print wires, said method comprising the steps of:effecting relative movement at an essentially constant velocity betweenthe head and record member; selectively actuating said wires atpredetermined intervals to form spaced imprints in a preset number ofspaced rows, each row being spaced by a full position of distance dwhere d is equal to or greater than the distance d'' traveled by saidhead in the minimum time required to actuate a given wire twice andwhere ( 1/2 <d'',) 1/2 d< d'', and; selectively actuating said wires forimprinting said record member at half positions between and overlappingadjacent spaced rows in the plane normal to the direction of relativemovement between the member and head with each actuation of a given wireforming imprints spaced by at least a distance d'' from the previousimprint of said given wire for forming the angular extending portions ofthe characters desired to be printed.
 2. The method of printing asdefined in claim 1 wherein said step of effecting relative movementfurther comprises the step of scanning parallel noncolinear print lineson said recOrd member with a plurality of print wires arranged in astraight row.
 3. A printing head for printing on a record membercomprising a plurality of printing wires having a first end positionedadjacent said member and the second end positioned remote to saidmember, an actuator for each wire operable upon energization to propelsaid wire first end into contact with said member for leaving an imprintthereon, means for effecting relative movement at an essentiallyconstant velocity between the head and record member, a wire guidepositioned between the actuators and record member functioning to alignthe wires in a single row extending normal to the direction of relativemovement between the head and member, means for energizing saidactuators at preselected spaced positions along said member forimprinting said member to form a matrix of spaced dots formingcharacters desired to be printed, said matrix having rows separated byfull positions of distance d, where d is equal to or greater than thedistance d'' traveled by said head in the minimum time required toactuate a given wire twice, and where 1/2 d<d'', means for energizingselected ones of said actuators at intermediate positions between saidrows of said matrix and in vertical overlapping relationship with saidrows for forming angular extending segments of characters, each saidactuator being energized to form dots in said member spaced by at leasta distance d''.
 4. A printing head as defined in claim 3 wherein sevenprinting wires are positioned in a single row for printing a line ofimpressions extending normal to the direction of movement between thehead and record member.
 5. The method of printing characters on a recordmember with a wire printing apparatus having a print head including aplurality of print wires, comprising the steps of: effecting relativemovement at an essentially constant velocity between the head and recordmember with said wires scanning parallel noncolinear print lines acrossa plurality of character print positions on said member; selectivelyactuating said wires to form a matrix of dots forming the charactersdesired to be printed, the rows of said matrix being separated by adistance L where 2L is equal to or greater than the distance L''traveled by said head in the minimum time required to actuate a givenwire twice and where L<L'' and selectively actuating each given wire toform dots spaced by at least the distance L'' from the dot formed by theprevious actuation of said given wire.